Contact element holder

ABSTRACT

A contact element holder, in particular a brush holder for commutator or wiper ring machines, has a carrier that can be secured to the machine housing and at least one quiver, held on the carrier and pointing toward the rotor, for displaceably receiving a contact element, and also has decoupling elements which are disposed between the carrier and the quiver. To achieve good noise decoupling of the contact element from the machine housing and, in use in a commutator machine, for assuring good commutation quality, the decoupling elements are embodied and disposed such that the at least one quiver is capable of executing only a limited rotational pivoting distance about the rotor.

PRIOR ART

The invention is based on a contact element holder for electricallycontacting a rotor, and in particular on a brush holder for commutatoror wiper ring machines, as generically defined by the preamble to claim1.

Because of commutator nonconcentricities, commutator brushes ofcommutator machines, such as direct current small motors, cause abruptchanges at the transition from one commutator lamination to another, andsimilar noises that are transmitted via the brush carrier to the machinehousing and are radiated from there. To reduce these running noises,noise-decoupled brush holders are used.

To assure good-quality commutation, it is important that the brushholder be located centrally to the commutator axis. Deviations from thatcause asymmetries in the supply of electrical current, and the resultantforces are in turn the cause of noises. In the noise-decoupled brushholder, a certain flexibility of the brush quivers relative to the brushcarrier must be accepted, and hence the inaccuracy, linked with thisflexibility, of the central position of the commutator brushes makes thequality of commutation worse.

In a known noise-decoupled brush holder (German Patent Disclosure DE 4241 405 A1), the decoupling elements between the carrier and the brushquiver are embodied as spring-elastic ribs, which connect anintermediate carrier, which firmly receives the brush quivers, to thecarrier. Both the intermediate carrier and the carrier are embodied asplates that are located in the same plane. The ribs, embodied inmeandering form, are either located in the plane of the plates or extendperpendicular to the plates; in the latter case, the meandering patternpoints in the axial direction of the commutator. The two plates and theribs are embodied as an integral injection-molded part.

ADVANTAGES OF THE INVENTION

The contact element holder of the invention having the characteristicsof claim 1 has the advantage that a rotary decoupling of the quiversabout the rotor axis is attained without additional degrees of freedomof a translational or rotational type, and as a result, in use incommutator machines, the centered position of the commutator brushesrequired for good commutation is no worse than in a non-noise-decoupled,rigid brush holder. The fluctuations in frictional values, responsiblefor brush noise, between commutator laminations and commutator brushescause only a rotational rotation of the quivers and hence do not affectthe centered position of the commutator brushes. By varying thegeometry, position and number of the decoupling elements, the contactelement holder can be adapted in a targeted way and can thus be adaptedquite simply to different kinds of applications machines.

By the provisions recited in the other claims, advantageous refinementsof and improvements to the contact element holder disclosed in claim 1are possible.

Structurally, the contact element holder of the invention can berealized quite simply by providing that in a preferred embodiment of theinvention, at least three decoupling elements are provided, and eachdecoupling element has only one degree of freedom, and the decouplingelements are disposed between the carrier and the at least one quiversuch that the degree of freedom of each decoupling element extends inthe tangential direction to the rotor.

In a preferred embodiment of the invention, the decoupling elements aredisposed offset from one another in the circumferential direction bypreferably the same rotational angle, or in other words are disposed ina star pattern.

In a preferred embodiment of the invention, the quivers are disposed onan intermediate carrier, and the carrier and the intermediate carrierare joined together by the decoupling elements; preferably, thedecoupling elements are embodied as elastic, shallow ribs, each of whichis located in a plane that is radial to the rotor axis. The carrier andthe intermediate carrier are embodied as plates of insulating materialwhich are located in the same plane, and the elastic ribs extendperpendicular to the plates. As a result of this structural embodimentwith “upright decoupling elements”, the contact element holder requireslittle space, which is advantageous for accommodating additionalinterference suppression elements. Moreover, in the injection molding ofthe integral contact element holder, the decoupling elements are locatedin the unmolding direction, so that no additional transverse pushers inthe injection-molding tool are required.

DRAWING

The invention is described in further detail below in terms of exemplaryembodiments shown in the drawing. Shown schematically are:

FIGS. 1 and 2, each, a plan view of a brush holder for a small directcurrent motor, in a first and second exemplary embodiment, respectively;

FIG. 3, a section taken along the line III-III in FIG. 1;

FIG. 4, a section taken along the line IV-IV in FIG. 2.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The brush holder, shown in plan view in FIG. 1, for a commutator machineused as a small direct current motor, as an example of a contact elementholder, has a carrier 11, in the middle of which is a square recess 12in which an intermediate carrier 13 is located. The carrier 11 and theintermediate carrier 13 are embodied as disklike plates of insulatingmaterial and are joined together via a total of four elastic decouplingelements 14. The intermediate carrier 13 has a circular through opening15 for the passage through it of a commutator, not shown here, of thesmall DC motor.

For the small DC motor, embodied with two poles, the brush holder hastwo commutator brushes 16, which are each axially displaceably receivedin a brush quiver 17 that extends in the direction of the throughopening 15 and which are pressed against the commutator, in theinstalled state, by means of brush pressing springs, not shown here. Theelectrical connection cords of the commutator brushes 16 are identifiedby reference numeral 18. The brush quivers 17 are secured to theintermediate carrier 13. To that end, two projecting arms 131 areprovided on the intermediate carrier 13 and rest with play incorresponding lateral elongations 121 of the recess 12. The brushquivers 17 are made of metal and are secured to the arms 131. In analternative embodiment of the invention, the brush quivers 17 may bemade of insulating material, and in that case they are producedintegrally with the plate of insulating material of the intermediatecarrier 13 by injection molding, so that the arms 131 are omitted.

The four decoupling elements 14 are disposed in a star pattern, offsetfrom one another by the same circumferential angles, about the throughopening 12 in the intermediate carrier 13 and are fixed on one endbetween the brush quivers 17 on the intermediate carrier 13 and on theother on the carrier 11. Each decoupling element 14 has only one degreeof freedom and is disposed such that this degree of freedom extends inthe tangential direction to the commutator, or in other words to thethrough opening 15 that receives the commutator; it is understood thatthe brush holder is mounted in the motor housing in such a way that theaxis of the through opening 15 in the intermediate carrier 13 coincideswith the commutator axis. Because of the star-pattern arrangement of thedecoupling elements 14 with a tangentially oriented degree of freedom,the intermediate carrier 13, with the brush quivers 17 secured to it,can execute only a limited, rotational pivoting distance about thecommutator, so that the commutator brushes 16 that press against thecommutator are rotationally decoupled. Either no additional degrees offreedom, namely two rotational degrees of freedom and threetranslational degrees of freedom, exist, or they are negligible.

In the exemplary embodiment of FIG. 1, the decoupling elements 14 arerealized by means of elastic, shallow ribs 19, each of which is locatedin a plane radial to the commutator axis or to the axis of the throughopening 15. In the sectional view in FIG. 3, one such shallow rib can beseen in plan view. It has the shape of a U, with legs 191, 192 and ayoke 193 that connects the legs 191, 192. One leg 191 is secured to thecarrier 11, and the other leg 192 is secured to the intermediate carrier13. Preferably, the ribs 19 are integrally injection-molded to thecarrier 11 and intermediate carrier 13 in the injection molding of thoseelements, and simultaneously the brush quivers 17 are integrallyinjection-molded, so that the separate arms 131 on the intermediatecarrier 13 are omitted. The ribs 19 protrude at a right angle fromplates of insulating material that form the carrier 11 and theintermediate carrier 13, so that in the injection molding process, theribs are located in the unmolding direction, and no additionaltransverse pushers in the injection-molding tool are necessary.

The brush holder that can be seen in plan view in FIG. 2, in accordancewith a further exemplary embodiment, is conceived of on the samefundamental principle. Once again, the decoupling elements have only onedegree of freedom and are disposed between the carrier 11 and theintermediate carrier 13 in such a way that the existing degree offreedom extends in the tangential direction to the commutator, so thatthe brush quivers 17, with the commutator brushes located in them, arecapable of executing only a limited rotation about the commutator, andall the other degrees of freedom of the intermediate carrier 13 arepractically not present. Unlike the brush holder of FIG. 1, here theintermediate carrier 13 is embodied as a circular plate of insulatingmaterial, which rests with play in the likewise circular recess 12 ofthe carrier 11 also embodied as an plate of insulating material. Thenumber of decoupling elements that join the carrier 11 and theintermediate carrier 13 is reduced to the minimum number of threedecoupling elements 14. These are again arranged in a star patternrelative to the commutator axis, that is, the axis of the throughopening 15 for the commutator, and are each located in a plane that isradial to the commutator axis or to the axis of the through opening 15.As FIG. 4 shows, each decoupling element 14 is again embodied as ashallow elastic rib 19 which is U-shaped and protrudes at a right anglefrom plates of insulating material that form the carrier 11 and theintermediate carrier 13. In the same way as in FIGS. 1 and 3, the rib 19here is again solidly joined by one leg 191 to the carrier and by itsother leg 192 to the intermediate carrier 13. The yoke 193 is embodiedin curved form, unlike FIG. 3. Otherwise, the construction and mode ofoperation of the modified brush holder of FIG. 2 are identical to thoseof the brush holder in FIG. 1, so that reference may be made in thisrespect to the above description. Components of the brush holder of FIG.2 that match the components of the brush holder in FIG. 1 are identifiedby the same reference numerals.

The contact element holder, described as an example as a brush holderfor a commutator machine, for producing an electrical connection with arotor, in this exemplary embodiment with the commutator, can also beused in so-called wiper ring machines, such as synchronous machines witha wiper ring rotor. In that case, instead of the commutator brushes,so-called grinding brushes are inserted into the quivers and rest inspring-loaded fashion on at least one wiper ring, instead of acommutator. Moreover, the contact element holder described may be usedwherever an electrical touch contact is to be made between athree-dimensionally stationary current-carrying component and acurrent-carrying component (rotor) that rotates relative to it.

1-12. (canceled)
 13. A holder for electrically contacting a rotor of acommutator or wiper ring machine, the holder comprising, a fixed carrier(11), at least one quiver (17) held on the carrier (11) and pointingtoward a central through opening (15) for the rotor, for displaceablyreceiving an electrically conductive contact element (16), anddecoupling elements (14) disposed between the carrier (11) and thequiver (17), the decoupling elements (14) being embodied and disposedsuch that the at least one quiver (17) is capable of executing only alimited rotational pivoting movement about the rotor.
 14. The holder ofclaim 13, comprising at least three said decoupling elements (14), eachdecoupling element (14) having only one degree of freedom, thedecoupling elements (14) being disposed between the carrier (11) and theat least one quiver (17) such that the degree of freedom extends in thetangential direction to the rotor.
 15. The holder of claim 13, whereinthe decoupling elements (14) are disposed offset from one another in thecircumferential direction by preferably the same rotational angle. 16.The holder of claim 14, wherein the decoupling elements (14) aredisposed offset from one another in the circumferential direction bypreferably the same rotational angle.
 17. The holder of claim 13,further comprising an intermediate carrier, the at least one quiver (17)being disposed on the intermediate carrier (13) and the decouplingelements (14) joining the carrier (11) and the intermediate carrier (13)together.
 18. The holder of claim 14, further comprising an intermediatecarrier, the at least one quiver (17) being disposed on the intermediatecarrier (13) and the decoupling elements (14) joining the carrier (11)and the intermediate carrier (13) together.
 19. The holder of claim 15,further comprising an intermediate carrier, the at least one quiver (17)being disposed on the intermediate carrier (13) and the decouplingelements (14) joining the carrier (11) and the intermediate carrier (13)together.
 20. The holder of claim 17, wherein the decoupling elements(14) engage the intermediate carrier (13) with spacing from the at leastone quiver (17).
 21. The holder of claim 13, wherein the decouplingelements (14) are embodied as elastic, shallow ribs (19), each of whichis located in a plane that is radial to the axis of the central throughopening (15) for the rotor.
 22. The holder of claim 14, wherein thedecoupling elements (14) are embodied as elastic, shallow ribs (19),each of which is located in a plane that is radial to the axis of thecentral through opening (15) for the rotor.
 23. The holder of claim 15,wherein the decoupling elements (14) are embodied as elastic, shallowribs (19), each of which is located in a plane that is radial to theaxis of the central through opening (15) for the rotor.
 24. The holderof claim 16, wherein the decoupling elements (14) are embodied aselastic, shallow ribs (19), each of which is located in a plane that isradial to the axis of the central through opening (15) for the rotor.25. The holder of claim 17, wherein the decoupling elements (14) areembodied as elastic, shallow ribs (19), each of which is located in aplane that is radial to the axis of the central through opening (15) forthe rotor.
 26. The holder of claim 25, wherein each rib (19) is embodiedas U-shaped, with two legs (191, 192) and a yoke (193) joining the legs(191, 192), located in the radial plane; and wherein one leg (191) ofeach rib is secured to the carrier (11), and the other leg (192) issecured to the intermediate carrier (13).
 27. The holder of claim 26,wherein the carrier (11) and intermediate carrier (13) are embodied asplates of insulating material, and wherein ribs (19) protrude at asubstantially right angle from the plates of insulating material. 28.The holder of claim 27, further comprising at least one quiver (17)secured to the plate of insulating material forming the intermediatecarrier and is preferably of metal.
 29. The holder of claim 27, whereinthe at least one quiver (17) is embodied integrally with the plate ofinsulating material that forms the intermediate carrier (13).
 30. Theholder of claim 27, wherein the plates of insulating material, whichform the carrier (11) and the intermediate carrier (13), and the ribs(19) are integrally injection-molded.
 31. The holder of claim 13,comprising at least two quivers (17) offset from one another by the samerotational angle are present.
 32. The holder of claim 29, comprising atleast two quivers (17) offset from one another by the same rotationalangle are present.